1. Field of the Invention
This invention generally relates to a bicycle rotation detecting device. More specifically, the present invention relates to a bicycle rotation detecting device that can be used to detect a rotation state of a bicycle part (e.g., a bicycle wheel).
2. Background Information
Sometimes, a cyclometer is mounted on a bicycle to show the rotation state of a wheel, such as number of rotations of a wheel or a traveling speed of the bicycle. In order for the cyclometer to show the rotation state, a signal indicating information such as the number of rotations of a wheel has to be acquired by the cyclometer. In order to acquire such signal, detection of the number of rotations of a hub shell relative to a hub axle has been proposed. For example, a bicycle light assembly is disclosed in U.S. Pat. No. 7,410,278, in which a waving circuit is provided for detecting the speed by detecting the number of rotations of a hub shell based on the electrical signal produced by the alternating current generator in the hub.